Sarby, it sounds like you have too much accountability....to such an extent that transactions refer entirely to you and have no mention of the 'donor'. I would have thought that the transaction should say 'Mr Sarby POA for Mr & Mrs Sarby senior'.
I have accounts where I have to log on as my parents to make transactions (even though I am a registered POA). When I make a transaction it is in my parents name, therefore there is no accountability, the system does not know that I am making the transaction. What should happen IMO is that I should get a separate log on in my name, and therefore any transaction would identify that I made the decision. Some institutions are better than others...there is no guidance from the regulators I suspect.
If you don't like a way a company does business then find one that does. If enough people do that - and the company is aware of why they are leaving, then possibly they will change their systems.